Peter J. Jannetta
Peter J. Jannetta
Peter E. Sheptak and Peter J. Jannetta
✓ Total removal of huge acoustic neurinomas was carried out in 23 patients by means of a two-stage suboccipital transmeatal approach with microsurgical technique. There was no operative mortality. Good results were obtained in 18 (78%) of the patients who have returned to normal activities or full-time employment. Five patients (22%) have residual preoperative neurological deficits causing a reduced level of activity. All of these, except one, are able to care for themselves. None of the patients has had any further significant neurological deficit caused by the operative procedures. Anatomical integrity of the facial nerve was maintained in 17 patients (74%). Surgical technique, operative morbidity, and results are thoroughly discussed. The potential advantages of this technique are stressed.
Bruce R. Cook and Peter J. Jannetta
✓ The syndrome of tic convulsif consists of ipsilateral concurrent trigeminal neuralgia and hemifacial spasm. Since Cushing's 1920 description of this syndrome in three patients, 37 additional cases have been reported in the world literature. Of the 15 with adequate operative descriptions, 10 had vascular abnormalities and five had tumors. The authors report 11 cases of tic convulsif treated by microvascular decompression of both the fifth and seventh cranial nerves. At operation, 21 of 22 nerves were found to have root entry zone vascular compression. One trigeminal nerve was considered normal. One seventh nerve had a tumor displacing the anterior inferior cerebellar artery into its root entry zone. The average follow-up period in this series was 6 years 2 months (range 1 to 8½ years). Eight patients (73%) were pain-free, two (18%) had frank recurrences, and one (9%) had mild discomfort. Eight patients (73%) were totally free of facial spasm, and two others (18%) had only a trace of residual spasm. These results are comparable to those achieved by treating the individual syndromes with microvascular decompression. Therefore, microvascular decompression of both the fifth and seventh cranial nerves is recommended as the treatment of choice in tic convulsif.
Use of monopolar constant-voltage stimulation and EMG
Aage R. Møller and Peter J. Jannetta
✓ The authors describe a modification in the way the facial nerve is stimulated electrically during operations to remove medium and large-sized (> 2 cm) acoustic tumors. This consists of monopolar stimulation with low internal impedance. Proper use of this modified stimulation technique together with acoustic monitoring of the electromyographic responses of facial muscles helps to preserve facial nerve function in patients undergoing these operations, and also decreases the duration of the operation.
Daniel K. Resnick and Peter J. Jannetta
✓ A 37-year-old woman underwent microvascular decompression of the superior vestibular nerve for disabling positional vertigo. Immediately following the operation, she noted severe and spontaneous gagging and dysphagia. Multiple magnetic resonance images were obtained but failed to demonstrate a brainstem lesion and attempts at medical management failed. Two years later she underwent exploration of the posterior fossa. At the second operation, the vertebral artery as well as the posterior inferior cerebellar artery were noted to be compressing the vagus nerve. The vessels were mobilized and held away from the nerve with Teflon felt. The patient's symptoms resolved immediately after the second operation and she has remained symptom free. The authors hypothesize that at least one artery was shifted at the time of her first operation, or immediately thereafter, which resulted in vascular compression of the vagus nerve. To the authors' knowledge, this is the first reported case of a hyperactive gagging response treated with microvascular decompression. The case also illustrates the occurrence of a possibly iatrogenic neurovascular compression syndrome.